Development of Compact Thermal–Fluid Models at the Electronic Equipment Level

Abstract

The introduction of compact thermal models (CTM) into computational fluid dynamics (CFD) codes has significantly reduced computational requirements when representing complex, multilayered, and orthotropic heat generating electronic components in the design of electronic equipment. This study develops a novel procedure for generating compact thermal–fluid models (CTFM) of electronic equipment that are independent over a boundary condition set. This boundary condition set is estimated based on the information received at the preliminary design stages of a product. In this procedure, CFD has been used to generate a detailed model of the electronic equipment. Compact models have been constructed using a network approach, where thermal and pressure-flow characteristics of the system are represented by simplified thermal and fluid paths. Data from CFD solutions are reduced for the compact model and coupled with an optimization of an objective function to minimize discrepancies between detailed and compact solutions. In turn, an accurate prediction tool is created that is a fraction of the computational demand of detailed simulations. A method to successively integrate multiple scales of electronics into an accurate compact model that can predict junction temperatures within 10% of a detailed solution has been demonstrated. It was determined that CTFM nodal temperatures could predict the corresponding area averaged temperatures from the detailed CFD model with acceptable accuracy over the intended boundary condition range. The approach presented has the potential to reduce CFD requirements for multiscale electronic systems and also has the ability to integrate experimental data in the latter product design stages.